Process of producing iron and steel directly from the ore



K. A. F. HIORTH. PROCESS OF PRODUCING IRON AND STEEL DIRECTLY FROM THE ORE.

APPLIOATIOIg FILED JUNE 13,1912.

1, 1 12,007. a nted Sept.\29, 1914.

2 SHEETS-SHEET 1.

' 5 v I a -//7 [46/7/0/1' K. A. 1?. HIORTH. I reoonss OF PRODUCING men AND STEEL DIRECTLY FROM THE ORE.

APPLICATION FILED JUNE 13,1912. 7 1,1 12,007, Patented Sept. 29, 1914.

2 SHEETS-SHEET 2.

WWW M/nmssex: v Agr/ 5 -T ///0/7/7- gzwzw orn on KARL ALBERT FBEDRIK HIORTH, 0F GHBISTIANLA, NOBWAY rnocnss or rnonoeme'mon AND s'rEEL DIRECTLY snor THE one Specification of Letters latent. Patented 29, 19 14 Application filed June 13, 1912. Serial No. 708,576.

ToaZZ whom it may concern:

Be it known that I, KARL ALBERT FRED- RIK HIORTH, a subject of the King of Norway, residing at Christiania, Norway, have invented certain new and useful Improvements in Processes of Producing Iron and Steel Directly from the Ores, and I do hereby declare the following to be a full, clear, and exact description of the inven tion, such as will enable others skilled in the art to which it appertainsito make and use thesame, reference being had to the accompanying drawings, and to letters or figures of reference marked thereon, which form a part of this specification.

The present invention relates to the production of iron and steel directly from ores, and it has for its object aprocess in which there is employedia gaseous reduction agent clrculate'd in the system and supplied .with heat by means of an electric arc furnace. The process is characterized more particularly by the fact that the gas which is heated inthe electric arc furnace is circulated in such manner as to maintain by direct emission the temperature of the reduced iron andalso the temperature of the iron during its finishing treatment, the heat radiated from the furnace preferably being utilized to preheat the circulating gas, while additional heat is introduced into the system at the upper part of the ore charge to thereby effect an economical combined 'transmission of heat by combustion and the electric arc furnace. If all the heat for melting and reducing the iron is supplied by the electric arc furnace, about one-third horse-poweryear is required per ton of iron, but this amount may be reduced by the heat obtained from combustion, although in such an arrangement it is .desirable that the ore and coal be separated since coal mixed with ore reduces the CO0. (See Norwegian Patent No. 20,965, filed December 9, 1908 at the lower temperatures.

1 have found that heating by the electric arc is cheaper for higher temperatures and that the: heating by combustion is cheaper Furthermore, I have found that by utilizing the heat from combustion a powerful roasting and'loosening efl'ect is obtained, and that by supplying heat to the upper part of the ore charge the possibility of the iron coming into contact with the incandescentnitrogen is avoided to some extent.

There will not in case beany typical,

electrodes; furthermore the 'had 'to the concentrated zone of heat with the inconveniences of vaultsfetc, as in electric .furnames of the Herould type wherein there \is employed a low voltage current and carbon .heat together be uniformly thereby obtaining the utilization and effect of with the current of gas will distributed all over, most advantageous the Whole plant.

The process will be described more par-' ticularly in the following, reference being accompanying drawings in which v Figure 1 shows diagrammatically the arrangement of the several apparatus in a plant suitable for carrying out the present process,- and Fig. 2 illustrates diagrammatically in plan a somewhat modified arrangement of the apparatus.

In the drawings, 'similar letters of reference indicate corresponding parts Wherever used. y

.In the drawing A is the reducing shaft, B the generator, 0 C C washing apparartus, D a fan or other blast device, E electric sfiame-arc furnaces, and F "a steel furnace, constructed like a fore-hearth and arranged between the -flame-arc'furna ces and the shaft-furnace. a

- The gases employed for the reduction are produced from inferior coal in the generator B (placed as near as possible to A, see Norwegian Patent N 0. 19953, =filed April 3, 1908) preferably according to the Mond system or the likehwhereby all substancessuitable for fertilizing purposes and other substances are extracted from the gas. The pure gases thus obtained are driven by the fan D through the flame-arc furnaces E, in

which they are supplied with the necessary amount of heat, and from thence they are conducted through the steel furnace or the forehearth F arranged just in front of the shaft. In this forehearth, in which the finishingtreatmentoftheiron coming from the shaft is performed wholly or partially, the hot gases pass across the surface of the iron bathtliereby supplying the bath with the heat necessary for the steel making treatment. 'By supplying air at H the temperature above the steel bath may be further raised. From the forehearth the gas enters the shaft A in which it causes the ore to be reduced and the iron to be melted down,'the carbon dioxid thereby produced passing from the top of the shaft directly into the generator B in a similar manner as 3 stated in the previously mentioned Nor-v point the gas (after having passed through the blower or fan) is led through the pipe K to the upper part of the ore charge, as at X, to supply the additional heat mentioned above, the gas then being burned in the upper part of the charge. To effect the combustion of this gas, air is blown into the charge, together with the gas.

The carbon dioxid conducted to the generator together with aqueous vapor assists in maintaining the temperature-produced by s the combustion in the generator at a low value so that the least possible amount of the nitrogen of the fuel is lost. The temperature of combustion is kept at the proper value by the carbonic acid which comes from the shaft at approximately the proper tem- Jerature. The temperature may also be adusted by supplying some oxygen, it being possible thereby to obtain reduction gases entirely free of nitrogen.

The shaft A is charged with iron ore (and, if desired, with a small quantity of coal for carburation purposes up to about 1% and for eliminating the action of the carbonic acid that may be carried along with the reduction gases). Otherwise the carburation is suitably effected by blowing a carbon bearing material as carbon powder or crude oil, into the gas in front of the shaft, that is, into the steel furnace F. When so conducting the process as to reduce oflt' almost pure iron, a special small carbura-tion shaft L is preferably provided in front of the ore shaft thereby also obtaining a supply of carbon for carburation purposes and for compensating the action of the carbon dioxid aqueous and the vapor contents of the gas.

All parts of the plant made of brickwork are as far as possible so constructed as to enable them to be exchanged during the operation, and two sets may be provided with the electric flame-arc furnace and the Siemens furnace or the fore-hearth so that by inserting auxiliary gas pipes a continuous pair of said furnaces may be taken into use during the rebuilding of the other pair. Such arrangement is shown in Fig. 2.

In the fore-hearth F, in which the finishing treatment takes place wholly or partially, the supply ofheat, as mentioned above, is effected by means of the gas'& passing from the flame-arc furnaces. During the finishing treatment in the fore-hearth the iron may be drawn from the shaft furnace directly through the tap-hole T into a separate container Q (Fig. 2). The steel, the treatment of which has been finished in the fore-hearth, is tapped into molds M or into an electric furnace'N for expelling the gases.

Around the shaft furnace A and the upper from the top of the shaft A is led through the regeneration chambers B. This gas enters the-chambers R at S and leaves at V, passing therefrom to the chimney. When portion of the fore-hearth F and the flamearc furnaces E is arranged a jacket through which pass the gases coming from the washing apparatus, C C C, said gases being thereby preheated before being introduced into the furnaces E through the fan D.

In cases where a regeneration of the CO leaving the shaft does not take place, the same is blownas in ordinary Siemens steel furnaces alternately through ordinary regeneration chambers B (Fig. 2) arranged in combination with the fore-hearth 1*.

hen the electric furnace E and the forehearth F are in use, hot carbon dioxid gas the filling of the chambers R is sufiiciently heated, the supply of carbon dioxid gas is stopped and carbon monoxid gas is led from the pipe T into the heated chamber from which it passes in heated condition into the gas conduit at U, thus serving to preheat the gas applied to the flame arc furnaces.

The process above described may, of course, be varied in its details within wide limits without departing from the spirit of the invention, and may also for instance be carried out in the following manner. 1

The ore is according to this modification not reduced completely in the shaft, but the iron flows down into the fore-hearth in a state mixed with some dissolved oxid. The batlrin this furnace is then to be treated in the same manner as that usually employed in connection with Siemens furnaces for treating baths which have been reduced and afterward supplied with additional ore or oxidized in other ways. The bath is treated with slag in the ordinary way, carburized to the desired extent and oured either into ingot molds, or, if spec al quality is aimed at, into a special electric furnace for expelling the gases.

Claims.

1. The process of producing iron and steel directly from an ore ch erge, which consists in producing a gas rich in carbon oxid, purifying said gas, introducing air and a 115 part of said purified gas into the upper part of the. ore charge, electrically heating another part of the purified gas, and passing the electrically heated part of thegas over the metal melted down from the ore charge 12 and into the lower part of the ore charge; substantially as described.

2. The process of producing iron and steel directly from an ore charge made up of ore and a small proportion of carbon material, 12& which consists inproducing gas rich in carbon oxid, purifying said as, introducing air and a part of said puri ed gas into the uppenpart of the charge of ore and carbon material, electrically heating another part 18( rifying said. gas,

of the purified gas, and passing the electrically heated part of the gas over the metal melted down from the ore charge and into the lower part of the ore and carbon ma-' terial; substantially as described.

3. The process of producing iron and steel directly from an ore charge, which consists in producing a gas rich in carbon oxid, pu-

introducing air and a part of said purified as into the upper part of the ore charge, e ectrically heating another part of the purified as, passing the electricall heated part of t e gas over the metal me ted down from the ore charge and into the lower part ofthe ore charge, and utilizing the radiated heat to preheat the purified gas; substantially as described.

4. The rocess of producing iron and steel directly from an ore charge, which consists in producing a gas rich ,in carbon oxid, purifying said gas, introducing air and a part of said purified gas into the upper part of the ore charge, electrically heating another part of the purified gas, passing the electrically heated part of the gas over the metal melted down from the ore charge and into the lower'part of the ore charge, and simultaneously introducing a carbonbearing material into the lower part of the ore charge; substantially as described.

In testimony that I claim the foregoing as my invention, I have signed my name in presence of two subscribing Witnesses.

KARL ALBERT FREDRIK morru.

Witnesses: v

M. GU'rroRMsnN, N. SCHIANDER. 

